Usercane Bob
Usercane Bob is a formerly strong usercane located east-northeast of the Lesser Antilles. Bob formed from a tropical wave in September 2015, and later became the second-strongest usercane on record with maximum sustained winds of 220 mph. Bob was the nineteenth tropical cyclone, eighteenth named storm, twelfth hurricane and ninth major hurricane of the hyperactive 2015 Atlantic usercane season. On January 11, 2020, Bob underwent explosive weakening to a tropical userstorm. Meteorological History On September 7, 2015, a tropical wave developed over Western Africa. Early the next day, the wave exited the African coast and entered the extreme eastern Atlantic. A surface low pressure area formed that morning. An ASCAT pass revealing a closed circulation was present indicated that the tropical wave became a tropical depression around 23:30 UTC on September 8. Around 18:00 UTC the next day, it is estimated that the depression strengthened into a tropical storm, being named "Bob." Bob continued to gradually strengthen over the next few days, acquiring 50-mph winds by September 11. That weekend, a mid-level eye feature began to develop within Bob, and on September 15, it reached the surface and Bob was upgraded to a category 2 hurricane based on Dvorak estimates. Over the next two weeks, Bob changed very little in organization, initially because the strongest convection was displaced from the center. On September 29, wind shear increased, causing Bob to weaken back to a tropical storm. The weakened Bob struggled to intensify for the next few weeks, embedded in a moderate shear environment. However, by October 18, a new mid-level eye feature began to develop. This eye feature began to reach the surface by October 25, and after an ASCAT pass revealed winds of 110-115 mph, Bob unexpectedly underwent rapid intensification and became a category 3 usercane with maximum sustained winds of 115 mph. Steady Intensification Shortly after becoming a category 3, Bob's small eye rapidly cleared out, signaling continued intensification. On December 17, Bob acquired category 4 usercane status with maximum sustained winds of 130 mph. Bob then weakened back to a category 3 usercane on December 23 in an eyewall replacement cycle as winds briefly decreased to 125 mph. However, on December 28, the eyewall replacement cycle was complete and Bob reattained category 4 status. Bob began to suddenly rapidly intensify more than expected with Bob briefly reaching category 5 status on January 5. The category 5 status was short in duration, with Bob weakening back to a 155 mph category 4 usercane later that day. Bob's winds fluctuated between 155 and 160 mph over the coming three months before acquiring the status in April and maintaining it. Bob remained a Category 5 usercane for nearly four years straight, though it did briefly weaken to a Category 4 usercane in September 2016 due to a brief eyewall replacement cycle. In January 2020, Bob started to reach much cooler waters, and began to take on some extratropical characteristics. On January 11, explosive weakening finally occurred and Bob fell from Category 5 intensity to a tropical userstorm in less then a day. Category:Usercanes